The affix yat as well as the above affixes come after the word śīrṣaccheda in the Accusative -2nd case in the sense 'who deserves that under all circumstances'.,
Thus शिरश्छेदं नित्यमर्हति = शीर्षच्छेद्यः, or शैर्षच्छेदिकः ॥ The word शिरस् is changed irregularly into शीर्ष before the affix.,